Question #c5870

2 Answers
Sep 12, 2017

2.020* 10^23 atoms

Explanation:

First, convert grams of chromium to moles:

17.441 "g Cr" ("1 mol"/ "51.996 g Cr") = 0.335 mol Cr

Then convert from moles to atoms using Avogadro's Number:

0.335 "mol Cr" ("6.022*10^23 atoms"/ "1 mol") = 2.020*10^23 atoms Cr

Sep 12, 2017

"Number of chromium atoms"~=2xx10^23

Explanation:

We work out (i) the molar quantity of chromium....

"Moles of Cr" = (17.441*g)/(51.9961*g*mol^-1)

=0.3354*mol.

And (ii) we know that a mole specifies Avogadro's number of molecules, i.e. 6.022xx10^23*mol^-1, and so we take the product....

=0.3354*molxx6.022xx10^23*mol^-1=??